# Raw and Ledger

The bottom two layers of the stack do one job together: turn messy financial evidence into deterministic, structured records with provenance back to source.

### Raw Layer

The Raw Layer ingests financial evidence verbatim from authorized sources.

#### Sources

| Category                      | Examples                                              |
| ----------------------------- | ----------------------------------------------------- |
| **Banks and processors**      | Plaid, direct bank APIs, Stripe, Adyen                |
| **Custodians and brokerages** | Brokerage feeds, custodian APIs                       |
| **On-chain**                  | Wallets via Alchemy, contract event streams           |
| **ERPs**                      | NetSuite, SAP, Dynamics                               |
| **Accounting platforms**      | QuickBooks, Xero                                      |
| **Payroll**                   | Major payroll providers                               |
| **Documents**                 | Email-attached invoices and receipts, CSV/PDF uploads |

#### Storage rules

Artifacts are content-addressed by SHA-256, encrypted with tenant-scoped DEKs, and stored in Azure Blob.

| Property       | Value                                             |
| -------------- | ------------------------------------------------- |
| **Identifier** | `sha256:<hex>` over canonical bytes               |
| **Encryption** | AES-256-GCM with tenant-scoped DEK                |
| **Storage**    | Azure Blob with versioning and lifecycle policies |
| **Retention**  | Per-tenant, configurable per source               |

{% hint style="info" %}
**Nothing is interpreted at this layer.** The Raw Layer's only job is to be a lossless, replayable record. If the extraction logic changes, every higher layer can be rebuilt deterministically from Raw.
{% endhint %}

### Ledger Layer

The Ledger Layer normalizes raw evidence into standard linkable objects.

#### Record types

| Type                       | Purpose                                     |
| -------------------------- | ------------------------------------------- |
| `transactions`             | Money movements between accounts            |
| `balances`                 | Point-in-time and rolling balances          |
| `accounts`                 | Tenant-side and counterparty accounts       |
| `counterparties`           | Vendors, customers, employees               |
| `invoices`                 | Billed amounts, due dates, line items       |
| `obligations`              | Subscriptions, recurring charges, contracts |
| `cash_flows`               | Aggregations and forecasts                  |
| `assets` and `liabilities` | Holdings and debts                          |
| `permissions`              | Authorizations affecting the Ledger         |
| `events`                   | Lifecycle events tied to records            |

#### Provenance on every record

Every Ledger record carries:

| Field               | What It Contains                             |
| ------------------- | -------------------------------------------- |
| `raw_refs`          | The Raw artifact hashes that produced it     |
| `extractor_version` | The deterministic extractor that produced it |
| `confidence`        | A calibrated score from 0 to 1               |
| `supersedes`        | Optional pointer to the record this corrects |

#### Immutability

Records are immutable and append-only. Corrections are written as superseding records that reference what they correct.

```
record_v1: { id: "tx_001", amount: 1234.56, supersedes: null }
record_v2: { id: "tx_002", amount: 1234.65, supersedes: "tx_001" }
```

The history is preserved. Any reader can replay the chain to see how the value evolved.

### Why Ledger sits between Raw and Wiki

LLMs are excellent at language and pattern recognition and unreliable at arithmetic, deduplication, and reconciliation.

| Concern                                   | Right Place                        |
| ----------------------------------------- | ---------------------------------- |
| Arithmetic, deduplication, reconciliation | Ledger (deterministic)             |
| Fluent reasoning, narrative answers       | Wiki (LLM-driven, citation-backed) |

The Wiki is the place for fluent reasoning, not the source of financial truth. Ledger enforces a deterministic, machine-verifiable structure first, so Wiki always reasons over verified facts rather than reinterpreting raw documents on every query.

{% hint style="success" %}
This is the same separation that exists in any serious system between the database and the cache. Brain's Ledger is the database; the Wiki is the reasoning surface that points back to it.
{% endhint %}

### What's next

<table data-view="cards"><thead><tr><th></th><th></th><th data-type="content-ref"></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>🧠 The Wiki</strong></td><td>The memory graph that reasons over the Ledger.</td><td><a href="/pages/IDbmiD3RRs6QlgR8UT8z">/pages/IDbmiD3RRs6QlgR8UT8z</a></td><td></td></tr><tr><td><strong>🛡️ Audit and Proof</strong></td><td>How every Ledger change gets a verifiable history.</td><td><a href="/pages/PIgNXssgtEUZDLnC4b4d">/pages/PIgNXssgtEUZDLnC4b4d</a></td><td></td></tr><tr><td><strong>🌐 Sources API</strong></td><td>Connect a source through the API.</td><td><a href="/pages/EQ4MJytikUzDXJfFnfp5">/pages/EQ4MJytikUzDXJfFnfp5</a></td><td></td></tr></tbody></table>


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